President Obama yesterday rightly slammed opposition to the US-Iran deal that was reached over the weekend. The critics, unfortunately given far too much time by the media, are in a frenzy to stop the deal. They’re using extreme and overblown rhetoric and throwing everything that they can into the mix. It’s Munich! Iranian suitcase bombs will be blowing up in New York! We can’t negotiate with terrorists! What about human rights?! And so on.

But the accord is a done deal, and its effects are already being felt. The Iranian currency, the rial, is strengthening, and oil prices are falling. The Europeans are already talking about meeting in January to ease sanctions on Iran further. And for the rest of the world it’s sinking in: for the first time in thirty-four years, there’s a chance that the United States and Iran might do more than strike a limited deal to wind down Iran’s nuclear program. It’s possible that the two countries could reach a détente, and work together on problems from Syria and Afghanistan to terrorism, world energy problems, and—believe it not!—even Palestine.

Of course, it’s early—but there’s no going back now. The US-Iran accord has the potential to be a transformational event. Let’s count the ways.

First, it can vastly change the world oil market, and that’s a big part of the reason why Saudi Arabia is so worried. Iran’s oil output, at about 1 million barrels a day now, could almost instantly rise to 2.5 million b/d, and from there it could go up significantly, to as much as 4 million b/d or more. Already, world oil companies are quietly jockeying to take advantage of an opening in Iran, which needs hundreds of billions of dollars in investments to rebuild its production facilities, pipelines, export facilities and refineries. That’ll be good news for China, India, Japan and other consumers in East Asia, and along with rising output in recovering Iraq and Libya, it’ll add a lot to world production. Prices will fall, and among OPEC countries it’s Saudi Arabia that will have to absorb the shock. Saudi Arabia will be faced with the choice of getting far less for its exports, per barrel, or cutting back on its own production to keep prices stable. So, if you thought that Saudi opposition to the Iran deal was only about the Sunni-Shiite struggle for power in the Middle East, well, there’s more to it.

The accord is transformational in other ways, too. It changes the ground rules of the whole region. If Iran winds down its nuclear program, it will reap vast rewards in terms of expanded trade, investment and business with the rest of the world. That will help moderates in Iran—including the business class, led nominally by Ayatollah Ali Akbar Hashemi Rafsanjani, the billionaire mullah and former president—to gain momentum over the remaining ideological radicals who seek confrontation and who are still animated by the extreme-Shiite ideology that was put forward by the founder of the Islamic Republic, Ayatollah Ruhollah Khomeini. Every dollar, mark and yen that flows into Iran will bolster Iranian moderation and help Iran back away from its less-than-reasoned confrontational stance. So in conflicts in Syria, Iraq, Palestine, Bahrain, Afghanistan and elsewhere, where Iran has a role to play, Tehran could become a force for a peaceful, negotiated solution in partnership with the United States and the rest of the world. It’s already partially evident in Syria, where Iran could play an important role in the upcoming peace conference in January.

The elimination of Iran as a regional bogeyman could kick the props out from under the huge American military buildup in the Persian Gulf, Central Asia, the Indian Ocean and the eastern Mediterranean. Why ships tens of billions of dollars in weapons to Saudi Arabia and the Persian Gulf kleptocrats and maintain bases in Bahrain, Qatar and elsewhere when there’s no regional military threat? It will be harder for the US military-industrial complex to justify those sales, and for the Pentagon to justify its bases, when Iran is a cooperating actor.

Despite the bluster in Israel and Prime Minister Benjamin Netanyahu’s nervous breakdown over the accord, eventually the normalization of Iran’s role in the region will make it a lot harder for future Israeli voters to justify their own armed-camp approach to the region. It will be much easier for Israel to think about a just settlement of the Palestinian issue if and when Iran is no longer a threat.

As for Russia, well, the US-Iran deal will be a concern, too. For decades, Moscow has taken advantage of the breakdown in US-Iran relations by building economic and military ties to Iran and using the churning regional crisis to its advantage. Now Russia will have to recalculate. And not just on political and military issues: if Iran re-enters the world community, it will compete with Russian gas sales worldwide, directly challenging Russia for the in the European and Asian gas markets. One way Russia can use the accord for its advantage, though, has already emerged: Foreign Minister Sergei Lavrov has said that now that Iran won’t be a nuclear threat, the United States and NATO can forget about putting an anti-missile system in Eastern Europe, since the last remaining, thin rationale for that was to deal with supposed missile threat from Iran.

This only begins to cover the possible transformation stemming from the accord. It has huge implications for domestic politics, too, since American neoconservatives have puffed up Iran into a global bogeyman to justify all sorts of shenanigans, and they are about to lose that “big time,” as Dick Cheney might say. Watch for neocons to make their own “pivot” to Asia, warning about the rise of China and the need for the United States to confront the Chinese worldwide.

Katrina vanden Heuvel says the Republicans are waging war on the poor.